This invention relates to a spacer for brazing used for spacing apart plural half-finished products, each comprising at least two plate-shaped workpieces layered together and bound by a brazing filler metal, are to be put one upon another and introduced into a brazing furnace.
In general, a spacer of this kind is used by inserting it between adjacent layers of the half-finished products in order to prevent fused brazing filler metal in a furnace from flowing into a gap between the adjacent half-finished products and binding the products together. In this case, if a usual steel plate is used as the spacer, a problem occurs because steel is high in wettability in relation to the brazing filler metal. Consequently, the spacer and the product are liable to be bound together by the fused brazing filler metal which flows into a gap therebetween.
Accordingly, it has been usual hitherto that a ceramic plate such as an alumina plate is used for the spacer. However, this kind of plate is defective in that it is weak in durability to thermal shock and cannot withstand repeated uses. Accordingly, alumina plates are considered to be consumable articles. This results in a lowering in productivity and a rise in cost.